Allow backspacing into custom emoji

Stephen Paul Weber created 2 years ago

When the platform wants to backspace into an imagespan, remove the span.
Some platforms remove the whole span when you backspace, some don't,
this at least makes it not weird on those that do not.

Change summary

src/main/java/eu/siacs/conversations/ui/widget/EditMessage.java | 52 ++
1 file changed, 51 insertions(+), 1 deletion(-)

Detailed changes

src/main/java/eu/siacs/conversations/ui/widget/EditMessage.java

@@ -9,7 +9,11 @@ import android.preference.PreferenceManager;
 import android.text.Editable;
 import android.text.InputFilter;
 import android.text.InputType;
+import android.text.Spannable;
 import android.text.Spanned;
+import android.text.SpannableStringBuilder;
+import android.text.TextWatcher;
+import android.text.style.ImageSpan;
 import android.util.AttributeSet;
 import android.view.KeyEvent;
 import android.view.inputmethod.EditorInfo;
@@ -20,6 +24,8 @@ import androidx.core.view.inputmethod.EditorInfoCompat;
 import androidx.core.view.inputmethod.InputConnectionCompat;
 import androidx.core.view.inputmethod.InputContentInfoCompat;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
@@ -49,10 +55,12 @@ public class EditMessage extends AppCompatEditText {
 
     public EditMessage(Context context, AttributeSet attrs) {
         super(context, attrs);
+        addTextChangedListener(new Watcher());
     }
 
     public EditMessage(Context context) {
         super(context);
+        addTextChangedListener(new Watcher());
     }
 
     @Override
@@ -79,7 +87,6 @@ public class EditMessage extends AppCompatEditText {
         return AUTOFILL_TYPE_NONE;
     }
 
-
     @Override
     public void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
         super.onTextChanged(text, start, lengthBefore, lengthAfter);
@@ -206,4 +213,47 @@ public class EditMessage extends AppCompatEditText {
 
         boolean onTabPressed(boolean repeated);
     }
+
+    public static class Watcher implements TextWatcher {
+        protected List<ImageSpan> spansToRemove = new ArrayList<>();
+
+        @Override
+        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+                if (s instanceof SpannableStringBuilder && ((SpannableStringBuilder) s).getTextWatcherDepth() > 1) return;
+            }
+
+            if (!(s instanceof Spannable)) return;
+            Spannable text = (Spannable) s;
+
+            if (count > 0 && text != null) { // something deleted
+                int end = start + count;
+                ImageSpan[] spans = text.getSpans(start, end, ImageSpan.class);
+                synchronized(spansToRemove) {
+                    for (ImageSpan span : spans) {
+                        if (text.getSpanStart(span) < end && start < text.getSpanEnd(span)) {
+                            spansToRemove.add(span);
+                        }
+                    }
+                }
+            }
+        }
+
+        @Override
+        public void afterTextChanged(Editable s) {
+            List<ImageSpan> toRemove;
+            synchronized(spansToRemove) {
+                toRemove = new ArrayList<>(spansToRemove);
+                spansToRemove.clear();
+            }
+            for (ImageSpan span : toRemove) {
+                if (s.getSpanStart(span) > -1 && s.getSpanEnd(span) > -1) {
+                    s.removeSpan(span);
+                }
+            }
+        }
+
+        @Override
+        public void onTextChanged(CharSequence s, int start, int count, int after) { }
+    }
 }